1. Field of the Invention
The present invention relates to a semiconductor device, a method of manufacturing the same, and a camera.
2. Description of the Related Art
A solid-state image sensor such as a CCD or CMOS sensor used in a digital camera or cellular phone may have a structure in which a solid-state image sensing chip is mounted in a package having a cavity, wires are connected to the chip by wiring connection such as wire bonding, and the chip with the wiring connection is airtightly sealed by fixing a light transparent lid member using an adhesive.
In the solid-state image sensor, a phenomenon in which depending on the use environment or the elapsed time, moisture gradually enters the interior of the package through the adhesive portion to increase the amount of vapor of the interior may occur. Therefore, when the solid-state image sensor reciprocally moves between environments with a large difference in temperature, condensation occurs inside the light transparent lid member or on the image sensing chip, so a desired image cannot be obtained.
Japanese Patent Laid-Open No. 2002-124589 discloses a method of locally providing a portion, that is not coated with an adhesive, in the adhesive portion between the package body and the glass plate to allow air circulation between the interior and exterior of the package using this portion as a ventilation portion.
If the thickness of an adhesive used to adhere the package body and the glass plate is too small, the stress resistance lowers, and the adhesive becomes prone to peeling upon a change in ambient temperature; or if this thickness is too large, the moisture resistance lowers. For this reason, the thickness of the adhesive is normally adjusted to about 5 to 30 μm. Therefore, as in Japanese Patent Laid-Open No. 2002-124589, when a portion that is not coated with an adhesive is locally provided in the adhesive portion between the package body and the glass plate, the size of the gap between the package body and the glass plate becomes 5 to 30 μm, so particles with a size equal to or smaller than 5 to 30 μm may enter the internal space of the package. Since the pixel size in the recent solid-state image sensor is about 1 to 5 μm, particles with a size larger than the pixel size may adhere onto a pixel.
The entrance of particles to the internal space of the package may be problematic in a semiconductor device such as an LED as well.